Mu'awiya ibn Haida said: "I asked the Messenger of Allah, towards whom should I be dutiful?" He said: "Your mother." I asked, "Then towards whom?" He replied: "Your mother." Again, I asked: "Then towards whom?" He answered: "Your mother." I said, "Then towards whom should I be dutiful?" He said: "Your father, and the next nearest relative and then the next nearest." (Reported by Imam Bukhari in al-Adab al-Mufrad, narration number 3).
"And your Lord has decreed that you not worship except Him, and to parents, good treatment. Whether one or both of them reach old age [while] with you, say not to them [so much as], "uff," and do not repel them but speak to them a noble word." (17:23)